See this bird? Pretty cute, huh? Just look at those irresistible, beady little eyes and that triumphant, majestic composure. Well, don’t be fooled. This bird is a troll. This bird is the common cuckoo.
Now, you might already be familiar with cuckoos thanks to cuckoo clocks (which are designed to make the exact same sound as a common cuckoo, by the way), but you’re probably not as familiar with their behavior. In the warmer months, common cuckoos are prevalent in Europe and Asia. Here, they breed before returning to Africa for the winter, and they have a highly unusual and troll-like breeding habit.
You see, common cuckoos are brood parasites, so instead of raising their own young, they trick other birds into raising their young for them. So how do they do this? Well, first, the female common cuckoo approaches the nest of a much smaller bird, usually a Eurasian reed warbler, a meadow pipit, or a dunnock. Due to her coloration, she greatly resembles a sparrowhawk, which temporarily frightens the smaller birds off their nests.
Then, in 10 seconds, she lays her own egg among the smaller bird’s eggs. The egg’s color and pattern will vary based on the species of bird the cuckoo is targeting, but the results are the same. In a particularly horrifying twist, the baby cuckoo hatches early and pushes the smaller bird’s own eggs out of the nest, ensuring that it does not need to compete with any other babies for attention. Thus, if the common cuckoo isn’t a troll, we don’t know what animal is.
